Customers who purchase Charcoal Machine equipment aim to earn money by selling the charcoal produced by the Charcoal Machine. However, if the charcoal produced does not meet standards, it will not sell in the market. Here is how to identify charcoal quality. Charcoal of different quality levels can be defined by the following aspects:
1. Carbon Content
The carbon content of charcoal varies with the type of raw material and the carbonization temperature. Generally speaking, compared with low-density woods such as poplar or paulownia, hard miscellaneous wood has higher carbon content under the same carbonization temperature. For the same raw material, high-temperature carbonization yields higher carbon content than low-temperature carbonization. Typically, the carbon content of charcoal is less than 75%. Taking pine as an example, when the carbonization temperature reaches 380°C, its carbon content is 76%; when the temperature reaches 500°C, the carbon content reaches 85%; and when the temperature reaches 600–700°C, the carbon content reaches 92%.
2. Moisture Content
Since charcoal is a highly absorbent substance, it absorbs moisture from the air, increasing its own moisture content. Therefore, the moisture content of charcoal has little impact on its own quality, except that customers require charcoal moisture content to be as low as possible to improve its economic value. Generally speaking, freshly discharged charcoal has a moisture content of less than 3%.
3. Ash Content
Ash content refers to the white or pinkish substance remaining after charcoal is completely burned, commonly known as ash. Its level directly affects the use and economic value of charcoal. For example, substances such as straw and rice husk contain high ash content that does not easily fall off during combustion, resulting in low combustion temperatures, making them unsuitable for domestic and industrial charcoal use. The ash content of charcoal varies with the carbonization process and temperature. However, for wood or its offcuts, the ash content difference after carbonization is not significant. Generally speaking, under the same conditions, charcoal made from broadleaf forests has higher ash content than that from coniferous forests, and charcoal made from raw materials with a higher bark ratio also has higher ash content. Typical charcoal ash content ranges from 1–4%.
4. Volatile Matter Content
The volatile matter content depends on the carbonization temperature. Depending on different uses, we can produce low- or medium-temperature charcoal, as well as high-temperature charcoal. The former releases volatile substances such as CO, CO2, H2, CH4, and gaseous carbohydrates during high-temperature calcination, with content generally ranging from 12–20%. High-temperature charcoal releases fewer of the above volatile substances, with content generally less than 5%.
5. Calorific Value
The energy released per kilogram of charcoal under specific conditions, expressed in calories. The calorific value of charcoal is directly related to the carbonization temperature and holding time. Under the same carbonization temperature and holding time conditions, different raw materials produce charcoal with different calorific values. Generally speaking, the higher the carbonization temperature and the longer the holding time, the higher the carbon content and naturally the higher the calorific value. When the carbonization temperature is below 450°C, the calorific value of charcoal made from wood and its offcuts typically ranges between 6,500–7,000 kilocalories per kilogram, while the calorific value of straw and rice husk charcoal is generally around 6,000 kilocalories per kilogram. When the carbonization temperature exceeds 600°C, the calorific value of charcoal made from the above materials can increase by 500–1,000 kilocalories.
